BLAS/SRC/dgemmtr.f(3)

NAME
BLAS/SRC/dgemmtr.f

SYNOPSIS

  Functions/Subroutines
subroutine dgemmtr (uplo, transa, transb, n, k, alpha, a, lda, b, ldb, beta, c, ldc)
DGEMMTR

Function/Subroutine Documentation

  subroutine dgemmtr (character uplo, character transa, character transb, integer n, integer k, double precision alpha, double precision, dimension(lda,*) a, integer lda, double precision, dimension(ldb,*) b, integer ldb, double precision beta, double precision, dimension(ldc,*) c, integer ldc)

DGEMMTR

Purpose:

    !>
    !> DGEMMTR  performs one of the matrix-matrix operations
    !>
    !>    C := alpha*op( A )*op( B ) + beta*C,
    !>
    !> where  op( X ) is one of
    !>
    !>    op( X ) = X   or   op( X ) = X**T,
    !>
    !> alpha and beta are scalars, and A, B and C are matrices, with op( A )
    !> an n by k matrix,  op( B )  a  k by n matrix and  C an n by n matrix.
    !> Thereby, the routine only accesses and updates the upper or lower
    !> triangular part of the result matrix C. This behaviour can be used if
    !> the resulting matrix C is known to be symmetric.
    !>

Parameters
    UPLO

    !>          UPLO is CHARACTER*1
    !>           On entry, UPLO specifies whether the lower or the upper
    !>           triangular part of C is access and updated.
    !>
    !>              UPLO = 'L' or 'l', the lower triangular part of C is used.
    !>
    !>              UPLO = 'U' or 'u', the upper triangular part of C is used.
    !>

    TRANSA

    !>          TRANSA is CHARACTER*1
    !>           On entry, TRANSA specifies the form of op( A ) to be used in
    !>           the matrix multiplication as follows:
    !>
    !>              TRANSA = 'N' or 'n',  op( A ) = A.
    !>
    !>              TRANSA = 'T' or 't',  op( A ) = A**T.
    !>
    !>              TRANSA = 'C' or 'c',  op( A ) = A**T.
    !>

    TRANSB

    !>          TRANSB is CHARACTER*1
    !>           On entry, TRANSB specifies the form of op( B ) to be used in
    !>           the matrix multiplication as follows:
    !>
    !>              TRANSB = 'N' or 'n',  op( B ) = B.
    !>
    !>              TRANSB = 'T' or 't',  op( B ) = B**T.
    !>
    !>              TRANSB = 'C' or 'c',  op( B ) = B**T.
    !>

    N

    !>          N is INTEGER
    !>           On entry,  N specifies the number of rows and columns of
    !>           the matrix C, the number of columns of op(B) and the number
    !>           of rows of op(A).  N must be at least zero.
    !>

    K

    !>          K is INTEGER
    !>           On entry,  K  specifies  the number of columns of the matrix
    !>           op( A ) and the number of rows of the matrix op( B ). K must
    !>           be at least  zero.
    !>

    ALPHA

    !>          ALPHA is DOUBLE PRECISION.
    !>           On entry, ALPHA specifies the scalar alpha.
    !>

    A

    !>          A is DOUBLE PRECISION array, dimension ( LDA, ka ), where ka is
    !>           k  when  TRANSA = 'N' or 'n',  and is  n  otherwise.
    !>           Before entry with  TRANSA = 'N' or 'n',  the leading  n by k
    !>           part of the array  A  must contain the matrix  A,  otherwise
    !>           the leading  k by m  part of the array  A  must contain  the
    !>           matrix A.
    !>

    LDA

    !>          LDA is INTEGER
    !>           On entry, LDA specifies the first dimension of A as declared
    !>           in the calling (sub) program. When  TRANSA = 'N' or 'n' then
    !>           LDA must be at least  max( 1, n ), otherwise  LDA must be at
    !>           least  max( 1, k ).
    !>

    B

    !>          B is DOUBLE PRECISION array, dimension ( LDB, kb ), where kb is
    !>           n  when  TRANSB = 'N' or 'n',  and is  k  otherwise.
    !>           Before entry with  TRANSB = 'N' or 'n',  the leading  k by n
    !>           part of the array  B  must contain the matrix  B,  otherwise
    !>           the leading  n by k  part of the array  B  must contain  the
    !>           matrix B.
    !>

    LDB

    !>          LDB is INTEGER
    !>           On entry, LDB specifies the first dimension of B as declared
    !>           in the calling (sub) program. When  TRANSB = 'N' or 'n' then
    !>           LDB must be at least  max( 1, k ), otherwise  LDB must be at
    !>           least  max( 1, n ).
    !>

    BETA

    !>          BETA is DOUBLE PRECISION.
    !>           On entry,  BETA  specifies the scalar  beta.  When  BETA  is
    !>           supplied as zero then C need not be set on input.
    !>

    C

    !>          C is DOUBLE PRECISION array, dimension ( LDC, N )
    !>           Before entry, the leading  n by n  part of the array  C must
    !>           contain the matrix  C,  except when  beta  is zero, in which
    !>           case C need not be set on entry.
    !>           On exit, the upper or lower triangular part of the matrix
    !>           C  is overwritten by the n by n matrix
    !>           ( alpha*op( A )*op( B ) + beta*C ).
    !>

    LDC

    !>          LDC is INTEGER
    !>           On entry, LDC specifies the first dimension of C as declared
    !>           in  the  calling  (sub)  program.   LDC  must  be  at  least
    !>           max( 1, n ).
    !>

Author
    Martin Koehler

Further Details:

    !>
    !>  Level 3 Blas routine.
    !>
    !>  -- Written on 19-July-2023.
    !>     Martin Koehler, MPI Magdeburg
    !>

Definition at line 189 of file dgemmtr.f.

Author

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